#app {
  > header {
    display: flex;
    border-bottom: 1px solid #7f7f7f7f;
    flex-direction: row;
    > :nth-child(1) {
      flex: 1;
      display: flex;
      flex-direction: column;
      > :nth-child(1) {
        flex: 1;
      }
      > :nth-child(2) {
        display: flex;
        margin-bottom: 0.67em;
        gap: 5px;
        flex-wrap: wrap;
        > vscode-button > svg {
          margin-right: 2px;
        }
      }
    }
    > :nth-child(2) {
      @media screen and (max-width: 420px) {
        display: none;
      }
      display: grid;
      grid-template-columns: repeat(2, auto);
      grid-template-rows: repeat(2, min-content);
      font-family: -apple-system, BlinkMacSystemFont, 'San Francisco',
        'Helvetica Neue', 'Noto Sans', 'Noto Sans CJK SC', 'Noto Sans CJK',
        'Source Han Sans', 'PingFang SC', 'Segoe UI', 'Microsoft YaHei',
        sans-serif;
      margin: 10px;
      > div {
        padding: 6px 12px;
        background-color: var(--vscode-editor-background);
        > div:nth-child(1) {
          text-align: center;
        }
        > div:nth-child(2) {
          text-align: center;
          font-weight: 700;
        }
      }
      > div.haveTag {
        > div:nth-child(2) > :first-child {
          transition: transform 0.5s;
        }
        > div:nth-child(3) {
          position: relative;
          > div {
            position: absolute;
            top: 0;
            right: -30px;
            opacity: 0;
            transition: opacity 0.5s;
            backdrop-filter: blur(12px);
            background-color: var(--vscode-editor-background);
            box-shadow: 0 3px 8px var(--vscode-editor-foreground);
            border-radius: 7px;
            padding: 10px;
            margin: 10px;
            width: 200px;
            z-index: 114514;
          }
        }
      }
      > div.haveTag:hover {
        > div:nth-child(2) > :first-child {
          transform: rotate(180deg);
        }
        > div:nth-child(3) > div {
          opacity: 1;
        }
      }
      > div.haveTag:not(:hover) {
        > div:nth-child(3) > div {
          animation: fadeOut 0.5s;
        }
      }
      > div:nth-child(1),
      > div:nth-child(2) {
        border-bottom: 1px solid var(--vscode-editor-foreground);
      }
    }
  }
  div.problemSamples {
    > div {
      display: grid;
      column-gap: 10px;
      grid-template-columns: 50% 50%;
      @media screen and (max-width: 400px) {
        grid-template-columns: 100%;
      }
      > div {
        > h3 {
          margin: 0;
        }
      }
    }
  }
}
